Process of concentrating ores by flotation



Patented Dec. 7, 1926.

UNITED STATES v 1,610,217 PATENT OFFICE.

HAROLD WALTER ELLEY, OF WILMINGTON, DELAWARE, ASSIGNOR TO E. I, DU PONT DE NEMOURS & COMPANY, OF WILMINGTON, DELAWARE, A CORPORATION OF DELAWARE.

No Drawing.

This'invention relates to the recovery of valuable minerals by flotation, and more particularly to the recovery bymeans ofa certain class of'organic flotation agents.

It has been shown in United States Paten'ts Nos; 1,364,307, 71,364,308, 1,364,859 and 1,415,899 that aryl-subs'tituted thio-ureas and particularly .thio-carbanilide may be used advantageously in the flotation of minerals. While thio carban'ilide has been used commercially as a flotation-reagent, it has been necessary to use it-in solution in approximately our parts of ortho-toluidine,

Y Y and at the present time its use is negligible,

ith'aving been replaced by much more eflicient reagents.

I have discovered that' very highly selective flotation agents are formed if in the formation of substituted thio-ureas, aliphatic amines are employed instead of aromatic amines; The invention consists broadly, therefore, in a process for the flotation of oresby the aid of alkyl-substituted thioureas.

My new flotation agents have the following general graphical formula;

where R and R' represent the same or different substituted or unsubstituted aliphatic radicals such as ethyl, propyl, isopropyl, butyl, isobutyl, amyl, etc. A specific example of my new class of flotation agents is dibutyl-thio-urea. This compound is made by heating 2 molecular proportions of normal-primary-butyl amine with one molecular proportion of carbon disulphide in the-presence of .01 mol. of sulphur at'the refluxing temperature for 5-6 hours. At the-end of'the reaction any unconsumed carbon disulphideand butylamine are removed by steam distillation and the product is. heated, in-the presence of alcohol if necessary, until all dithio-carbamate has been transposed to the thio-urea. After -fil tration the dibutyl-thio-urea is dried and is ready for use.

Thi reggent was used for the flotation of Phelps-D ge Corporation Copper queen ore'in the ollowing manner: 500 gms. .of minus 28 mesh ore were ground for 20 min- 'utes in a pebble mill with 50000. of H,O,

0.6 .gnis. of lim'e,'and .025 gms. of dibuty thio-nrea. The lime and the dibntyl-thio- I 'phatic radicals.

PROCESS ,OF CONCENTBATING ORES BY FLOTA TIQN.

Application and April 24, 1925, Serial no, 25,701.

urea are in the proportion of 2.4 pounds and 0.10' pounds respectively per ton of ore. The pulp from the pebble mill was transferred to a J anney laboratory flotation machine, diluted to about 2 liters and a rougher concentrate removed for 10 minutes, water being added as needed; The following results were obtained, comparative results with thio-carbanilide being included:

Pounds 8 2 5 Per cent g? a? reagent eoneenm recovper ton tratetaflmgs ered Diliutyl-thio-urea a 10 s. 69 o. 34 so. 0 Thio-carbanilide o 40 4. 62 l. 30 16. 9

I I l 'r. 'r. mHtuIeS Z a 52 a 49 72.3

No frothing agent was used when e'mploy ing dibutyl-thio-urea since it functions both as a selective and a frothing reagent. With otherores, however, it may be necessary to employ a frothin agent.

though, in il ustrating my new process, reference has been made specifically to copper ore, to a certain dibutyl-thio-urea, and to various specific conditions of operation, it will be understood that my invention is not limited to these specific substances or'conditions, but includes generally processes of recoverin values from ores by flotation in which 518 flotation agents are alkyl-substituted thio-ureas.

- Although my flotation agents are effective to a certain extent in an acid pulp, better results are usually obtainable by operating 'of a substance having the following general molecular formula:

R'NHCS--NH-Rf where R and R represent-unsubstituted ali- 2- In .the process and minerals by'flotatiomthe step which of concentrating ores comprises subjecting the ore in the form of .a pulp to a flotation operation in the. presence of a substance having the following general molecular formula:

Where R andR' represent aliphatic hydrocarbon radicals.

3. In the process of concentratin ores and minerals by flotation, the ste w ich comprises subjecting the ore in t e form of a pulp to a flotation operation in the presence of a substance having the following,

general molecular formula:

RNH CS-NI- IR prises subjecting the ore in the form of a non-acid pulp to a flotation operation in the presence of a di-alkyl-thio-ureaQ 6. In the process of concentrating ores and minerals by flotation, the step which coms prises subjecting the ore in the form of a pulp made alkaline by the additionof lime to a flotation operation in the presence of a di-alkyl-thio-urea;

' 7. In the process of concentrating ores and minerals by flotation, the step which comprises subjecting the ore in the form of an alkaline pulp to a flotation operation in the presence of a di-alkvl-thio-urea.

8. A process as defined in claim 7 in which the alkyl groups of the di-alkyl-thio-urea each contain from 1 to 6 carbon atoms.

9. In the process of concentrating ores and minerals by flotation, the step which comprises subjecting the ore in the form'of an alkaline pulp to a flotation operation in the presence of a di-butyl-thio urea.

In testimony whereof, I aflix my signature.

HAROLD W.- ELLEY. 

